Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

45.  ORGANOCHLORINE ACCUMULATION IN MIDDLE MISSISSIPPI RIVER SHOVELNOSE STURGEON: INTERSEXUALITY AND REPRODUCTIVE CONSEQUENCES

Brian Koch *, Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6511; Phone 618-536-7761; Fax 618-453-6095; bkoch@siu.edu

James E. Garvey, Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6511; Phone 618-536-7761; Fax 618-453-6095; jgarvey@siu.edu

Michael J. Lydy, Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6511; Phone 618-536-7761; Fax 618-453-6095; mlydy@siu.edu

Organochlorines were used to control agricultural pests, subterranean termites, and mosquitoes on lands adjacent to the middle Mississippi River (MMR) during 1948 through 1988. Consequently, high concentrations of the organochlorine chlordane have been found in shovelnose sturgeon (Scaphirhynchus platorynchus) in this system, leading to multiple consumption advisories. Because organochlorines can disrupt steroidogenesis in males and produce intersexual fish, we quantified organochlorine accumulation, intersexuality, and resulting reproductive effects in male shovelnose sturgeon from urban and agricultural sites throughout the MMR during spring 2003. Testes were removed and observed for feminine traits, weighed to calculate a gonadosomatic index, and then stored for contaminant and histological analysis. Brains and fillets were also removed to assess tissue-specific accumulation. Four out of 59 males were macroscopically identified as intersexuals, and another was found to be intersexual through histology. Preliminary analysis of samples suggests significant accumulation of organochlorines in all tissues. Accumulation of organochlorines may impair reproductive ability of this species and its congener, the federally endangered pallid sturgeon (S. albus).